Common Disease Problems
Aster Yellows: Plants are stunted, develop witch's brooms (excessive growth), petals turn green and become deformed. This virus-like condition is spread by leafhoppers. Burpee Recommends: Remove infected plants and control leafhoppers. Remove weeds in the area which serve as alternate hosts to the disease.
Bacterial Leaf Spot: First signs are small translucent spots with a broad yellowish edge that slowly enlarge and become angular or irregularly circular with a reddish center. It thrives in cooler temperatures. The disease may also affect and disfigure flower heads. Burpee Recommends: Remove infected plants. Avoid overhead watering. Do not work around plants when they are wet.
Powdery Mildew: This fungus disease occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.
Rust: A number of fungus diseases that cause rust colored spots on foliage and stems. Burpee Recommends: Remove infected plants. Contact your Cooperative Extension Service for recommendations.
Virus (Various causes): The most characteristic sign of virus is tight and dark green mottling of the leaves. Young leaves may be bunched. Young plants may have a yellowish tone and become stunted. Fruit is usually not affected in outward appearance, but it may be smaller and scarcer. Leaflets may point upward and have a grayish cast. Burpee Recommends: Destroy diseased plants and the plants on either side.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects that can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Leafhoppers: Leafhoppers cause injury to leaves and stunt growth. They also spread disease. Burpee Recommends: Remove plant debris. Use insecticidal soaps. Consult your Cooperative Extension Service for other insecticide recommendations.
Slugs: These pests leave large holes in the foliage or eat leaves entirely. They leave a slime trail, feed at night and are mostly a problem in damp weather. Burpee Recommends: Hand pick, at night if possible. You can try attracting the slugs to traps either using cornmeal or beer. For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole; use something that has steep sides so that the slugs can’t crawl back out when they’re finished. Fill the bowl about ¾ of the way full with beer, and let it sit overnight. In the morning, the bowl should be full of drowned slugs that can be dumped out for the birds to eat. For a cornmeal trap, put a tablespoon or two of cornmeal in a jar and put it on its side near the plants. Slugs are attracted to the scent but they cannot digest it and it will kill them. You can also try placing a barrier around your plants of diatomaceous earth or even coffee grounds. They cannot crawl over these.
Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.
Spittlebugs: These hopping insects protect themselves from predators with a white foam while the young insects feed on the leaves and stems. When the insects emerge they are hoppers with large "froggy" eyes. There is only one generation each year but the larvae can hatch over a period of several weeks as the eggs were laid in the fall. Burpee Recommends: To control wash the foam off with a strong water spray. This will usually also kill the larvae. Do this once or twice a week for as long as needed. The damage is usually minimal.
Can I grow solidago in a container? We do not recommend solidago for containers because it is very large, and it only blooms late in the season. Mix it with other perennials in a border or wild planting.
Is solidago deer resistant? Yes, it does tend to be deer resistant.
Is solidago a good pollinator plant? Yes, it is a real magnet for bees!
Why are so many people allergic to goldenrod? People are not very allergic to goldenrod, but many people are allergic to ragweed, which blooms at the same time. Goldenrod is much showier than ragweed and has often been blamed for the allergy symptoms.
Why didn’t my solidago bloom, it’s in full sun? If you fertilized the plant or if the soil is too rich is may produce foliage at the expense of flowers. Do not fertilize.